Add aconfig flag value text file in aconfig_declarations provider

Alongside with the generated proto file, the aconfig_declaration now
also outputs a text file that lists aconfig flags and values of its
corresponding proto file, in the format as shown below:
```
my.flag1=true
my.flag2=false
...
```

To prevent confusion between the preexisting proto file and the newly
introduced text file, the change also renames the variables of the proto
file from `intermediatePath` to `intermediateCacheOutputPath` and
likewise.

The utilization of the generated text file will be done in the child
changes.

Test: m out/soong/.intermediates/build/make/tools/aconfig/aconfig.test.flags/intermediate.txt && inspect output
Bug: 306024510
Change-Id: Iee16ad57bb87e992a477fc96502f79e971d01233

aconfig/init.go

@@ -40,6 +40,19 @@ var (
 			Restat: true,
 		}, "release_version", "package", "declarations", "values", "default-permission")
 
+	// For create-device-config-sysprops: Generate aconfig flag value map text file
+	aconfigTextRule = pctx.AndroidStaticRule("aconfig_text",
+		blueprint.RuleParams{
+			Command: `${aconfig} dump --format bool` +
+				` --cache ${in}` +
+				` --out ${out}.tmp` +
+				` && ( if cmp -s ${out}.tmp ${out} ; then rm ${out}.tmp ; else mv ${out}.tmp ${out} ; fi )`,
+			CommandDeps: []string{
+				"${aconfig}",
+			},
+			Restat: true,
+		})
+
 	// For all_aconfig_declarations: Combine all parsed_flags proto files
 	AllDeclarationsRule = pctx.AndroidStaticRule("All_aconfig_declarations_dump",
 		blueprint.RuleParams{